Gear grinder



July 24, 1928.

C. KNOWLES GEAR GRINDER Filed Dec. 1924 5 Sheets-Sheet IILVENTOR Canno'flwnoweu ATTORNEY July 24, 1928.

C. KNOWLES GEAR GRINDER Filed Dec. 5, 1924 5 Sheets-Sheet NVEIVTUR W IITTORNEY July 24, 1928.

C. KNDWLES GEAR GRINDER Filed Dec. 1924 3 Sheets-Sheet 5 v INVENTOR Mww-(u BY 4/ ATTORNEY Patented July 24, 1928.

. UNITED S TES PATENT OFFICE.

CARROLL KNOWLES, OF HARTFORD, CONNECTICUT, ASSIGNORTO PRATT & WHITNEY COMPANY, .OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

- GEAR GRINDER.

- Application filed December a, 1924. Serial No. 753,651.

This invention relates to gear grinding machines and in particular to a machine which will rapidly and accurately reproduce 1nvolute, or other tooth forms, upon the flanks 5 or sides of gear teeth.

An object of the present invention 1s to provide an improvedgear grinding machine which is adapted to rapidly grind narrow faced gears within a wide range of dlameters to a'high precision upon a tooth form copying principle.

One feature which enablesme to accomplish the above named object is that the gear blank is so mounted that it may, in effect, be

' rolled past one or more grinding wheels upon its base or other circle while mounted on a spindle, and, between each complete rolling movement of thegear blank, may be withdrawn directly from engagement with the wheel or wheels and indexed. After having been indexed, the gear blank may then be advanced toward'the wheels to re-engage them upon other of its teeth.

Another object of the invention is to provide means to completely grind each of the tooth curves of a gear blank to an identical curve or tooth form, this curve being of involute or of a modified involute form, the shape of which is controlled by the form of a upon a part of the base of the machine.

Another feature which is advantageous is that I mount the templet removably' upon the spindle carrying the gear blank, this tem let having an involute or other curved sur ace dependent upon the type of gear being ground. This curved surface is adapted to be engaged, during operation preferably with a plane surface on the abutment .fixed adjustably to a part of the base or frame of the machine. I A

Another object of the invention is to provide a form of gear grinder, similar in many respects to that shown in my Patent No. 1,611,047, granted December 14, 1926, with templet means to reproduce tooth curves on the blank being ground. Also, it is a further object of the invention to provide adjustably positioned abrasive wheels adapted to engage opposite sides of adjacent or alternate teeth upon their plane radial surfaces and to provide means for mounting the gear blank spindle and the blank that they may templet carried upon the' spindle and co operating with a fixed abutment provided be given simultaneous rotative and reciprocatory movements to simulate the rolling action of a gear upon circles of difierent radii.

With these and other objects in view, my invention consists in the features of construction and operation set forth in the following specification and illustrated in the accompanying drawings.

In the accompanying drawings annexed hereto and forming a part of this specification, I have shown my invention embodied in a spur gear grinding machine adapted for gears having relatively narrow" faced teeth but it will be understood that the invention can be otherwise embodied and that the drawings are not to be construed as defining or limiting the scope of the invention, the claims appended to this specification being relied uponfor that purpose.

In the drawings:

Figure 1 is a front elevation of the complete gear grinding machine made in accordance with the present invention.

Fig. 2 is a plan view of the complete grinding machine.

Fig. 3 is a central transverse sectional view in elevation showing themeans to actuate and index the spindle carrying the gear blank.

Fig. 4 is a sectional view taken upon line 4-4 of Fig. 3.

In the above mentioned drawings, I have shown but one embodiment of the invention which is now considered preferable, but it is to be understood that changes and modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

Briefly, and in its broadest aspect, the gear.

grinder comprising my invention includes the following principal parts; first, a base; second, a pair of wheel slides mounted on .the upper horizontal surface thereof and arranged so that the wheels carried thereby may be adjusted to definite angular and radial ositions depending upon the size and type o fgear being ground; third, a longitudinally reciprocatory supporting slide mounted upon a slide movable forwardly and rearwardly; fourth, means for actuating the slides and parts connected thereon toward and from the wheels and longitudinally along the base; fifth, an abutment fixed during operation to the base and mounted adjacent thework spindle; sixth, a member fixed upon and movable with the work spindle having a curved surface adapted to be held in contact with the abutment during operation to cause the spindle to be rotated during reciprocations of the slide; and seventh, indexing mechanism adapted to be operated during the cycle of operations.

Referring more in detail to the figures of the drawings, I provide a base member 10 provided on its upper surface with ways 11 upon which a slide 12 may be moved forward and rearward by any desired means. This slide 12 carries ways 13 on its upper surface disposed at right angles to the previously referred to ways 11 and on these latter ways 13 is a carrier or slide 14 carrying a verti-v cally disposed rotatable work spindle 15. Means for effecting a movement of the lower slide 12 toward and from suitably positioned abrasive wheels 16 are provided comprising in part a connecting rod 17 attached at. its forward end to this slide 12. As the means for actuating this rod 17 during the cycleof operations of the machine are or may be identical with those disclosed in my copending application, a discription of this mechanism is not thought to be necessary. It will be sufiicient to state that the slide 12 is moved back and forth to engage and disengage the gear blank A with the Wheels 16 during operation of the machine, the movement of the blank A out of engagement permitting indexing.

In rear of the machine and mounted upon the upper horizontal surface of the base 10 are wheel heads 18 on which are rotatably mounted the abrasive wheels 16. These wheels 16 and their mountings or heads 18 are in all respects similar to those disclosed in the above referred to copending application and further description is not thought to be necessary. They preferably may be adjusted angularly or toward and from each other to adapt them for different types or sizes of gear blanks being ground. Also, the mechanism for actuating the slides 12 and 14 carrying the work spindle 15 to'eflect the rolling, feeding and indexing movements of the blank A are or may be identical with those of my 00 ending application and so need not be furt er described.

The present invention relates primarily to the mechanism for effecting the rolling movements of 'the blank A during which it is in engagement with the cutting surfaces of the abrasive wheels. For this the longitudinally movable slide 14 is adapted to be constantly reciprocated by any desired means such as the crank 20 shown in Fig. 3. Mounted on the .Work spindle 15 is a cam member 21 having a curved cam surface 22 upon one portion adapted to bemaintained in contact with an abutment-23 fixed during operation to a part of the base or purpose,

frame 10 of the machine. These parts are most clearly shown in Fig. 4 of the drawings. As will be seen by reference to this figure, the abutment 23 is carried upon a bar 24 fixed rigidly to brackets 25 forming ex- 1 tensions to a part of the machine frame 10.

On this bar 24 the abutment 23 is angularly adjustable and has a plane surface 26 upon 'one of its sides. To permit angular adjustment of this abutment 23, it is pivoted to a lateral projection on the bar 24 as shown at 27 and is held in adjusted angular position by a screw 28 extending through an arcuate slot in, the abutment 23. In order to hold the curved surface 22 of the cam 21 on the work spindle 15 in contact with the plane surface 26- of the abutment 23,. a helical spring 29 is provided, one end of which is attached to an extension 30 on the cam member 21 and the opposite end is made fast to a part 31 forming portions of the longitudinally reciprocatory slide 14. The contact of the cam surface 22 with the plane surface 26 0f abutment 23 during the reciprocations of the slide 14 cause a rotative motion of the spindle 15. This rotative motion combined with the simultaneously reciprocatory motion simulates a rolling motion of the blank A upon a pitch circle.

As the usual forms of tooth curves on spur gears are involutes, the cam surface 22 is usually of involute form but it will be understood that iftooth curves of other forms are desired, it is only necessary to modify the form of this curved surface. Also different cams 21 having curved surfaces of different involute or other form will be required for difl'erent gears; If the gear being ground is of involute form, the base circle of the particular involute on the cam surface 22 mountedonthe work spindle will be of the same diameter as that of the gear A being ground. For convenience, the cam member 21 is made removable to permit different cams of different involute or other form being readily substituted.

The indexing mechanism comprising worm :32 and gear 33 also shown in Fig. 4 is identical with that disclosed in, my copending application, the cam member 21 preferably being mounted just above the indexing gear 33 and keyed to the work spindle 15 by meansof a spline or key 34.

What I claim is: j

0 1. A gear grinding machine comprising in combination, a base, a rota able grinding wheel thereon, a work suppo ting spindle, means to reciprocate the spindle past the wheel, an abutment fixed during operation having a plane surface thereon, a plate mounted on said spindle and having a curved surface adapted to'contact with theplane surface on said abutment, whereby reciprocation of the spindle simulates a rollingmotion of a gear blank thereon, and

2. A gear grinding machine comprising i in combination, a base, a rotatable grinding wheel thereon, a work supporting spindle, means to reciprocate the spindle past the wheel, anabutment fixed during operation having a plane surface thereon, a plate mounted on said spindle and having an involute surface of the same base circle as the gear being ground adapted to contact with the plane surface on said abutment, whereby reciprocation of the spindle simulates a rolling motion of a gear blank thereon, and means to disengage the wheel from the blank during operatlon to permit intlexing.

A gear grinding machine comprising in combination, a base, a rotatable grinding wheel thereon, a work supporting spindle, means to reciprocate the spindle past the wheel, an abutment having a plane surface fixedly attached to the base during operation, a plate having a curved surface thereon mounted on the spindle and adapted to contact with said plane surface whereby reciprocation of the spindle simulates a-rol1-' ing motion of a gear blank thereon, means resiliently forcing said plate against said abutment, and means to radially withdraw the blank from the wheel during operation while the abutment'remains in contact with the plate to permit indexing.

4. A gear grinding machine comprising in combination, a base, a rotatable grinding wheel thereon, a work supporting slide, a spindle rotatably supported thereon, means to reciprocate the slide past the wheel, an abutment having a plane surface thereon fixedly attached to the base during operation, a plate having an involute. surface thereon mounted on the spindle and adapted to contact with said plane surface whereby reciprocation of the slide simulates a rolling motion of a gear blank thereon, means resiliently forcing said plate against said abutment, means to periodically index said spindle relative to said plate, and means to radially withdraw the blank from the wheel during operation while the abutment remains in contact with the plate to permit indexing.

5. A gear grinding machine comprising in'combination, a base, a rotatable grinding wheel thereon, a work supporting spindle,

means to reciprocate the spindle past the wheel, an abutment on the base having a plane surface thereon, a cam member on the spindle having an involute surface of the same base circle as the gear being ground adapted to engage said plane surface for rotating the spindle simultaneously with its reciprocatory movement to simu late a rolling motion of a gear blank on said spindle, means resiliently forcing said cam member against said abutment, means to relatively feed the wheel and spindle toward each other during its reciprocatory motion, means to index the gear blank during operation, and means to radially withdraw the blank from the wheel during operation while the abutment remains in contact with the plate to permit indexing.

6. A gear grinding machine comprising in combination, a base, a rotatable grinding wheel thereon, a work supporting spindle, means to reciprocate the spindle past the wheel, an abutment on said base adapted to be angularly adjusted and having a plane surface thereon, cooperating cam means on said spindlehaving ,an involute surface adapted to engage said plane surface in any position of adjustment to rotate the spindle during its reciprocator movement to simulate a rolling motion 0 a gear blank on said spindle, means resiliently forcing said involute surface toward said plane surface, means toindex the gear blank during operation, and means to radially withdraw the blank from the wheel during operation while the abutment remains in contact with the plate to permit indexing.

In testimony whereof, I ereto afiix my signature.

CARROLL KNOWLES. 

